Abstract: Traditional approaches for treating fundus diseases, such as topical eyedrops and oral administration, are minimally invasive but often yield suboptimal therapeutic outcomes due to poor intraocular penetration caused by physiological ocular barriers. In contrast, intravitreal, subretinal, and periocular injections achieve better efficacy but carry risks of ocular trauma and infection. In recent years, considerable progress has been made in the development of non-invasive drug delivery strategies for fundus diseases. For instance, cell-penetrating peptides—used either in direct drug conjugation or as part of drug carrier systems—significantly enhance the ability of therapeutics to cross ocular barriers and reach the posterior segment. Similarly, drug carriers such as hydrogels, novel nanoliposomes, and contact lenses can prolong ocular surface retention time, thereby indirectly improving drug delivery to the fundus. More recently, an integrated wearable system with an electrically driven switch has been developed, which uses electrical stimulation to enhance ocular barrier penetration, enabling efficient non-invasive delivery of macromolecular drugs to the posterior eye.

Key words: Fundus diseases, Drug administration route, Non-invasive drug administration, Ocular barrier